"People living in the city do not know much about trees, their impact on environment and our lives and the need for forests," said Noazesh Ahmed, renowned photographer and agriculturist during the inaugural ceremony.

"A medium size mango tree provides oxygen for a family of 5 to 6. Imagine what a forest can do," he added.

Speakers at the inaugural function said the forest landscape of Bangladesh have changed dramatically over the years. In some parts of the country forest is now a thing of the past, especially the Sal forest.

Most of the government-owned forests are devastated for commercial logging and plantation of alien species that does not suit our environment, they said.

"Forests are not just its flora and fauna and the animal inhabitants. The forest dwelling communities, their knowledge, traditions, culture and the indigenous technology that they use every day are also part of a forest", said Ronald Halder, one of the filmmakers taking part in the festival.

"When forests are destroyed their lives are destroyed, along with it a rich culture," he added.

The photo exhibition reflects the distressing condition of the forests and the magnificence that it still has to offer.

Environmentalist Philip Gain said, "Objective of the documentary film show and photography exhibition is to educate city people about its importance and let them know the causes of forest destruction."

"We often blame the forest dwelling people for its destruction. In realty, they only collect what they need. They do not destroy forests for commercial purpose, which is one of the reasons for its destruction," he added.

"With the films and photography we want to reveal the main reason behind forest destruction to the city people," he said.

Gain blamed the mass plantation of foreign species in our nature without assessing its effect as one of the reasons for forest destruction. "We chopped down indigenous species and planted foreign species that are alien to our nature. These species namely Acacia have been proven a wrong choice for our nature."

Fourteen documentaries on the dying Sal forests, the magnificent Sundarbans, Tanguar Haor, Baikkar beel, and the painful state of Karnaphuli river, Sathchhari forest and Chokoria forest are being screened at the festival.

Organised by the Society for Environment and Human Development (SEHD), the exhibition will remain open to visitors from 3:00pm to 8:00pm every day until May 24. Documentary shows on forests, adivasi life and nature are being screened from 5:00pm to 7:00pm every day.